> For the complete documentation index, see [llms.txt](https://docs.n8n.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.n8n.io/integrations/builtin/cluster-nodes/sub-nodes.md).

# Sub-nodes

Sub nodes attach to root nodes within a group of cluster nodes. They configure the overall functionality of the cluster.

[Cluster nodes](/key-concept-glossary.md#cluster-node-n8n) are node groups that work together to provide functionality in an n8n workflow. Instead of using a single node, you use a [root node](/key-concept-glossary.md#root-node-n8n) and one or more [sub-nodes](/key-concept-glossary.md#sub-node-n8n) that extend the functionality of the node.

![Screenshot of a workflow with a root node and two sub-nodes](/spaces/GixZThfitWP21x2gQFpD/files/GbA7RoHTpD75RG5oDkF8)